Constant tension drive for web reels



Aug. 7, 1951 J. A. L. REBUT ET AL CONSTANT TENSION DRIVE FOR WEB REELS .Filed Jan. 4, 1950 INVENTOR JACQUES A. L REBUT,

PmRRE CHERIGIE ORNEY Patented Aug. 7, 1951 CONSTANT TENSION DRIVE FOR WEB REELS Jacques Albert Louis Rebut and Pierre Cherigi, Paris, France, assignors to La Cellophane, Paris, France, a French company Application January 4, 1950, Serial No. 136,812 In France January 12, 1949 This invention relates to take-up reels for continuous webs and particularly to winders for webs of fragile material, such as regenerated cellulose or the like, and has for an object to provide a drive which maintains the web under constant tension during the entire winding operation.

Another object is to provide a positive drive for l the take up reel with constantly varying speed to maintain a constant web speed regardless of the diameter of the winding and with a further modification of the reel speed as required to maintain a constant web tension.

Other objects and advantages will be apparent as the nature of the invention is more fully disclosed.

There are known means of winding webs of film, e. g. of regenerated cellulose, by means of a reel slidably mounted on a positively driven shaft. The web is delivered at constant speed, at the outlet from the drier, and as the diameter on the reel increases there is more and more slippage between the reel and the shaft. As it is necessary to wind at constant tension, attempts have been made to devise a drive using a roller in contact with the surface of the wind ing, but such a drive requires perfect line contact in order to be effective. It does not lend itself to high winding speeds, which are increasingly coming into use, and it tends to produce n defective non-cylindrical windings because of slippage against the drive roller. Various methods have also been contemplated for winding on a positively driven reel with compensation of the speed of rotation as a function of the increasing momentary diameter of winding, but these meth- 4 Claims. (Cl. 242-75) ods do not allow for the tension of the strip being wound.

The present invention provides a winding device for continuous webs, particularly regenerated cellulose films, on a reel driven at a speed controlled by the initial tension of the web. In a specific embodiment the drive includes a differential having a cage driven at constant speed and having one gear driving the winding reel and the other gear drivinga pump the load of which is controlled as a function of the web tension. Specifically, the pump may comprise a gear pump delivering a suitable liquid circulating in a closed circuit containing a throttling valve whose opening is a function of the web tension.

The invention will be further described by reference to the accompanying drawing in which the figure is a schematic diagram illustrating one embodiment thereof.

In the drawing, a web I is reeled in a roll 2 on a reel 3. A tensioning roller 4 is mounted on an arm 5 pivoted at 6 and attached at the other end to one or more retaining springs I anchored at 8. The arm 5 carries an arm 9 acting on a pneumatic compressed-air regulator Ill of known construction such as a Sylphon bellows, which responds to the position of the arm 9 and hence to the position of the roller 4, which varies as a function of the tension of the web I ahead of the winding 2.

The sleeve 3 is fixed to a shaft 20 connected to a driven gear II of a differential, whose planet gear I3 is fixed to a housing or cage I2 which is connected to a worm gear 2| driven by a constant speed worm drive I4.

The other driven gear 22 of the differential I2 is mounted on a shaft I5 driving a gear pump I6 delivering a suitable liquid, such as mineral oil, in a closed circuit II. This circuit contains a variable aperture in the form of a throttling valve I8, operated by a pneumatic control diaphragm 23 connected by a tube I9 to the bellows III.

The speed of rotation of the gear II attached to the reel 3 is determined by the constant linear speed of the web I winding onto the roll 2. As the thickness of the roll 2 increases the speed of the gear I I must correspondingly decrease. Since the speed of the housing 12 of the differential is constant, there must be a resulting corresponding increase in the speed of the gear 22 which is determined by the load applied thereto by the pump Hi. This load is controlled by the throttling of the valve I8.

If, for example, the tension of the web I tends to increase, the arm 9, actuating the bellows I0, increases the opening of the valve I8 and allows the flow rate to increase, with acceleration of the pump IB, due to reduced back pressure. As a result the gear 22 speeds up and the gear II slows down and the winding rate is decelerated to compensate for the increased tension. The opposite effect takes place when the tension of the web I tends to decrease. Hence any variation in tension produces a change in valve opening in a direction to restore the tension to its original value.

The device provides for winding under constant tension or under tension varied in any systematic manner, for cellulose webs leaving a drier, a waterproofing column, a cutter for cutting into narrow strips, etc., and also for any other continuous Web of such materials as paper, fabric, etc. In all these cases, the invention permits 3 the preparation of perfectly symmetrical and uniform rolls of greatly increased weight because of the constant winding tension and absence of slippage. For example cellulose film two meters in width may be rolled in rolls Weighing 350 kg., instead of only about 100 kg. as heretofore.

What is claimed is:

1. A winding device for a continuous web comprising a reel on which said web is wound, a feeler positionable by the web and shiftable in response to variations in web tension, a difierential having a cage and a pair 01' driven gears, means driving said cage at constant speed, one of said gears being connected to drive said reel, 9. pump driven by the other of said gears, and means responsive to said feeler to vary the load on said pump.

2. A winding device for a continuous web comprising a reel on which said web is wound, a feeler positionable by the web and shiftable in response to variations in web tension, a differential having a cage and a pair of driven gears, means driving said cage at constant speed, one of said gears being connected to drive said reel, a pump driven by the other of said gears and delivering a liquid into a closed circuit, a throttling valve in said 4. In a winding device, as set forth in 61mm 2,

a diaphragm responsive to fluid pressure connected to control said valve, said ieeler being connected to control the pressure on said diaphragm.

' JACQUES ALBERT LOUIS REBUT.

PIERRE CHERIGIE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,652,229 Carpenter Dec. 13, 1927 1,884,784 Marcalus Oct. 25, 1932 2,064,295 Crane Dec. 15, 1936 2,200,160 Davis May 7, 1940 2,392,226 Butterworth et a1. Jan. 1, 1946 

